Posted
by
samzenpus
on Wednesday June 25, 2014 @07:30PM
from the up-against-the-wall dept.

meghan elizabeth writes: Temple physicist Rongjia Tao has a utopian proposal to build three massive, 1,000-foot-high, 165-foot-thick walls around the American Midwest, in order to keep the tornadoes out. Building three unfathomably massive anti-tornado walls would count as the infrastructure project of the decade, if not the century. It would be also be exceedingly expensive. "Building such walls is feasible," Tao says. "They are much easier than constructing a skyscraper. For example, in Philadelphia, the newly completed Comcast building has about 300-meter height. The wall with similar height as the Comcast building should be much easier to be constructed."Update: 06/28 04:14 GMT by T: Note: originally, this story said that Tao was at Drexel rather than Temple -- now corrected

As an earthmoving project, each kilometer of wall is 18M cubic meters. The Panama Canal was about 250M cubic meters of earthmoving. So every 14KM of wall is one Panama Canal. The proposed Arabian Canal [wikipedia.org] near Dubai (to create "valuable waterfront property" accessable by yacht) would require about 1100M cubic meters of earthmoving. So one Arabian Canal is about 60KM of wall.

In terms of speed, one Bagger 288 [wikipedia.org] can move about 250K cubic meters of earth a day. That's 5KM of wall per year. With one such $100 million machine for every 100KM of wall, the project would take 20 years.

On the other hand, building a concrete *anything* that is a thousand feet tall and 165 feet thick isn't easy. They're claiming that a one-mile stretch of the wall would cost $160 million, which comes out to 871.2 million cubic feet of concrete, or a cost per cubic foot (including labour and materials) of about $0.18. That sounds really unlikely to me.

Let me put it this way, the hoover dam is actually relatively similar to what we're talking about here. It's roughly 700 feet tall, varies from 45 to 600 feet thick, and is about a fifth of a mile wide... So let's say that the cross section of the hoover dam has about the same area as this proposed wall.

OK, so now we just need the length of the wall. Well, the circumference of the American midwest is roughly 3900 miles (cutting through the great lakes, because what the hell). So basically, what we need to do, is build the equivalent of roughly 20,000 hoover dams.

The hoover dam cost the equivalent of about $750 million to build. I suspect it would cost a lot more today than pure inflation would account for (unions, health and safety standards, etc), but let's say that technological progress would counteract all that...

There's a fairly easy way the death toll due to tornadoes could be lowered over time in states like Oklahoma, Kansas, Missouri, etc -- adopt the same building codes we have in South Florida.

Most people don't realize it, but South Florida experiences the most urban tornadoes per square mile per year in the entire United States. Granted, we basically never see EF4 and EF5 tornadoes... but we get plenty of the smaller ones.

The strength of South Florida tornadoes is EGREGIOUSLY under-reported by the Enhanced Fujita scale, because the EF scale is defined primarily in terms of observed damage rather than measured wind speeds -- damage that just doesn't happen in Florida, even with directly-comparable storms. An EF1 tornado capable of wiping a neighborhood of matchstick McMansions off the map would barely make a dent in a neighborhood of concrete post-Andrew South Florida homes with large-missile impact glass windows (Google "ASTM 1886-1996"), and would probably be reported as an EF0 unless it hit a trailer park or a neighborhood with older homes. An EF1 tornado is basically 30 seconds of a category 1 or 2 hurricane... and a direct hit by a category 1 hurricane is the South Florida equivalent of a snow day in upstate New York.

Anyway, the point is, if homes in suburban Kansas were built from reinforced concrete, deaths from anything short of an outright EF5 monster would basically fall into the category of "rare, unfortunate freak accidents" in areas where all the buildings were built to Dade County standards.

Driverless cars weigh more, but if you put the car on a rail and let a computer drive it would move 10x faster on 10x less energy and have no accidents. I added the costs that it would take to build a system like that and then realized it would pay for itself in 5 years.

Welcome to Europe. Let me introduce you to this wonderful technology called "TRAINS" that we have here.We've scaled up your plan a bit (they also transport 100x the number of passengers).We've also jumped on the "electrical vehicle" bandwagon while we're at it (very few are still diesel powered)(also there's a human in front who can override the system just in case, though some metropolitan transport have gone 100% driverless).

Actually, it's a common misconception to think that the Great Wall was built as a military defense mechanism in the event of full scale war. For one, it's too low, easily scalable by an army with the right tools. And secondly, it's too long, and can never be effectively manned along the full length. All in all, the Great Wall was never designed to function like a city wall.

What the wall really does, and it does well, is act as a deterent and early warning mechanism against the annual and semi-annual small scale border raids from the northern nomadic tribes, where riders would just charge down south, loot what they can and quickly retreat back into the great prairies. It's actually a (relatively) economical answer to a persistent problem -- for it's very expensive for a settled agricutural civilization to mobilize an army, while it costs almost nothing for the nomads to gather up a group of riders and raid a small border settlement.

And BTW, China is far from the only one in building a wall. Almost every settled civilization on the Eurasian continent, from Korea [wikipedia.org] all the way [wikipedia.org] to England [wikipedia.org], built a wall at some point in their history. The Chinese wall was the largest simply because China face the greatest threat from the Mongolian plains, which produced some of the most brutal and effiecient nomadic people in human history.